91057765 has 4 divisors (see below), whose sum is σ = 109269324. Its totient is φ = 72846208.

The previous prime is 91057751. The next prime is 91057783. The reversal of 91057765 is 56775019.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 48246916 + 42810849 = 6946^2 + 6543^2 .

It is a cyclic number.

It is not a de Polignac number, because 91057765 - 2¹⁹ = 90533477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9105772 + ... + 9105781.

It is an arithmetic number, because the mean of its divisors is an integer number (27317331).

Almost surely, 2^91057765 is an apocalyptic number.

It is an amenable number.

91057765 is a deficient number, since it is larger than the sum of its proper divisors (18211559).

91057765 is a wasteful number, since it uses less digits than its factorization.

91057765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18211558.

The product of its (nonzero) digits is 66150, while the sum is 40.

The square root of 91057765 is about 9542.4192425192. The cubic root of 91057765 is about 449.8892978719.

The spelling of 91057765 in words is "ninety-one million, fifty-seven thousand, seven hundred sixty-five".